LONDON – It's not quite the changing of the guard but U.K. commercial broadcaster Channel 5 has beaten fellow broadcaster Channel 4 in viewer share for the first time since Channel 5's launch in 1997.

In what is described by The Guardian as "the tiniest of margins," Channel 5's flagship channel managed to hit just shy of a 5 percent share of total viewing, including its +1 timeshift service, when that was added in.

Channel 4's main network, including its Channel 4+1 channel, posted a 4.94 percent share of what is called "all individuals" viewing between 6 a.m. and 1 a.m. last week.

A report in The Guardian notes that while Channel 5's margin of victory may be small, its first ratings win over Channel 4 is still a landmark for what is called a core channel comparison.

Channel 5, currently terrestrial home to a slew of U.S. hits including Justified and The Mentalist, garnered the strong viewers' tally on the back of homegrown hits Big Brother and The Ashes cricket highlights show of the competition between England and Australia that lands in the U.K. every four years.

Interestingly, both the cricket highlights and Big Brother used to be Channel 4 commissions, airing on the broadcaster's main channel until 2004 and 2010, respectively.

The viewer share figures do not include Channel 4's catchup channel, 4Seven, because Channel 5 does not have an equivalent service.